Hydraulic well jar



July 10, 1962 L. w. CHENAULT 3,043,373

HYDRAULIC WEL;J JAR Filed Deo. 8, 1,959 2 Sheets-Sheet 1 Fig' Fig. 2

F ig. 5

Lou/'s n. Chenoa/f INVENTOR.

` s BY @Zwam ad/WMLW July 10, 1962 1 .w. CHENAULT 3,043,373

HYDRAULIC WELL JAR Filed Dec. 8, 1959 2 Sheets-Sheet 2 Fig. 6

Lou/'s M. Chenoa/f INVENTOR.

BY WWW# @Mm 3,i}43,373 Patented July 10, 1962 3,943,373 HYDRAULIC WELL.IAR Louis W. Chenault, 5015 Evergreen Lane, Victoria, Tex. Filed Dec.8, 1959, Ser. No. 858,178 14 Claims. (Cl. 166-178) This inventioncomprises a novel and useful hydraulic Well jar and more particularlyrelates to a device adapted to be connected to a drill string, a stringof pipe or tubing or a wire line and to a fishing sub for automaticallyand by hydraulically controlled means effecting an upward jar or blowupon the shing sub connected theretO.

In Working deep wells such as those employed for recovering oil, gas orthe like from great depths in the earth it is frequently necessary torecover a broken or stuck piece of pipe, rod, or the like, which hasbecome accidentally or ina-dvertently stuck in the hole. A customaryprocedure for lthis purpose is to connect a 'fishing sub, suspended by awire line, drilling or -tubing string to the upper end of the stuckpiece of pipe, or rod, cornmonly known as a fish and then etiectmechanical blows or jars to the latter in order to loosen the same andfacilitate its recovery.

It is therefore the object of the present invention to provide animproved hydraulically operated jar for this purpose.

A further object of the invention is to provide a hydraulically actuatedjar in accordance with the foregoing object in which through thesuitable control of 4the flow of hydraulic uid therein, and in responseto actuation f the jar by an upward pull upon the wire line, tubing ordrill string to which the jar is attached, there is eiiected an initialslow upward movement of the hammer piston component of the jar until ata predetermined portion of its upward 4travel in the barrel of the jar arelatively free upward movement is permitted to thereby enable a violentblow, impact or jar to tbe applied to the barrel of the tool and thus tothe iish secured to the lower end thereof.

A further important object of the invention is to provide ahydraulically actuated jar in accordance with the preceding objects,which will enable a relatively rapid reverse travel of the piston hammerWithin the jar in order to reset the device for use in effecting asubsequent jar or blow. y

A further important object of the invention is to provide ayhydraulically operated jar in accordance with the foregoing objectwherein the jar itself shall be -of simple construction, being providedwith top and bottom closures, the former serving as an anvil upon whichthe piston hammer strikes and the latter serving as a control means toregulate the rate of movement and the action of the piston hammer withinthe jar.

A still lfurther object of the invention is to provide a hydraulic jarin accordance with the preceding objects wherein a very simple controlmeans for the hydraulic action is provided, the same including a bore orcontrol chamber formed in the lower end of the piston hammer, by-passpassages extending through the piston hammer and intersecting this bore,and with the control means consisting of a control piston carried by thebottom closure member and being slidably received within the bore andcontrolling communication of the by-pass passages therewith.

And a final important object of the invention to be speciicallyenumerated herein resides in the provision of a hydraulic jar whichshall be of simple, compact and inexpensive construction, yet one whichshall be highly effective and eiiicient for the 'purposes intended.

These together with other objects and advantages which will becomesubsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout, and in which:

FIGURE 1 is a View showing in section a-portion of a well bore andillustrating the manner in which the hydraulic jar inaccordance withthis inven-tion is disposed therein for operation by a drill string orthe like, the upper end of the jar being broken away and shown invertical section to indicate the position of the parts therein after thepiston hammer of the jar has delivered its impact -to the anvil at theupper end of the jar;

FIGURE 2 is a view similar to FIGURE `l but having a lower portion ofthe barrel of the jar broken away and showing the position of thepiston, of lthe jar at the lower end of the position and travel in thebarrel of the jar in readiness for beginning its upward hammer stroke;

FIGURE 3 is an enlarged view in vertical section through the jar showingthe internal construction of the piston hammer, the anvil and thecontrol means for the jar and indicating the manner of attaching the jarto the lower end of a drill pipe, tubing string or wire line, and

.showing the manner in which the lower end of the jar is attached to aishing sub;

FIGURE 4 is a horizontal sectional view taken substantially upon theplane indicated by the section line 4-4 of FIGURE 3;

FIGURE 5 is a perspective view of the closure plu-g for 4the bot-tom endof the jaw;

FIGURE i6 is a view similar to FIGURE 3 of the upper portion of the jar'but showing a slightly modified construction in which the well fluidmay be employed as the liquid medium for controlling the operation ofthe jar; and

FIGURE 7 is a horizontal sectional View taken su-bstantially upon aplane' indicated by section line 7-7 of FIGURE 6.

In FIGURES l and 2 of the accompanying drawings, the nu-meral 10`designates a portion of a well bore in which is shown suspended at 12 aportion of a suitable supporting actuating means for the jar whichitself is indicated by the numeral 14. Coupled to the lower end of thejar is a iishing sub 16 of any suitable construction and by means ofwhich the jar may be secured at the upper end of a piece of a stub pipe,tubing or other fish in order to loosen the same and permit Ithe fish tobe removed from the well bore after loosening.

The member shown 12 may consi-st of any of the usual means forsupporting and operating the jar such as a drill string, a string oftubing or pipe or the like, or even a wire line with an appropriateswivel for connecting the same to the jar.

Referring now especial-ly to FIGURE 3 it will be seen that the jar 14consists of a hollow body comprising a cylindrical barrel 20 which isopen and internally threaded at its top and bottom ends, being providedwith top and bottom closure plugs as at 22 and 24 respectively. In theembodiment of FIGURES 1-5, the top closure plug 22 is provided with acentral bore 26 therethrough provided with la suit-able O-ring or otherpacking .means 28 to establish a sealed engagement With the operatingstem 36 ofa piston and hammer 32 slidably received in the chamber in theinterior of the body 2th.

As will be observed from FIGURE 3, the piston ha-mmer 32 divides theinterior of the chamber into top and bottom compartments 34 and 36respectively, which compartments are filled with a suitable hydrauliciluid of any desired character which -is designed or intended to dampenand control the rate of travel of the piston hammer Within the chamberas set forth hereinafter.

The operating rod Sil which extends slidably through the bore 26 of thetop closure plug 22 is in turn provided with a connector 38 having anexternally threaded upper end l` received in the internally threadedbore 42 of the lowermost section of the string 12. The operating rod 30is preferably provided with a laterally enlarged or flanged port-ion asat 44 which is adapted to abut the upper end of the top closure plug 22to limit .downward travel of the piston hammer 32 and if desired toprevent the bottom surface of the latter from striking the bottomclosure plug 24.

It should here be understood that the top closure plug 22 comprises ananvil having a flat annular bottom surface 46 against which the topsurface of the piston harnmer 32 is adapted to strike or engage when thepiston hammer is moved tothe uppermost position in the top compartment34 of the barrel of the jar in the position shown in FIGURE l.

A hydraulic control means is provided for regulating the rate of travelof the piston hammer within the chamber of the hollow body in a mannerand for a purpose to be now described.

An axial bore 50 extends upwardly from the bottom face 52 of the pistonhammer 32 and into the operating rod 30 |to provide a control chamber 54therein. A plurality of by-pass passages 56 constitute by-pass meanswhich at one end intersect the previously mentioned bore 50 of thecontrol 'means adjacent lche lower end of the latter, land at theirupper ends open upon the annular shouldered surface S upon the top sideof the piston hammer 32 and thus establish communication with the uppercompartment 34. The by-pass means, except when controlled as set forthhereinafter does establish uninterrupted cornmunication Ibetween the topand bottom chambers 34 and 36. When the by-pass `means are open, it isobvious that the piston -is free to travel in the chamber and the hollowinterior of the body between its lowermost and its uppermost positionwithout substantial hindrance by the iiuid contained in these chambers,and th-us can deliver an impact or blow upon the Aanvil comprising thetop closure plug 22.

In order to facilitate downward or reverse movement of the piston withinthe chamber of the body there is provided a return means consisting ofone or more fluid return passages 66 whose upper ends intersect theby-pass passages 56 intermediate the ends of the latter, and Whose lowerends open as at 62 through the bottom surface 52 of the piston hammerinto the bottom compartment 36. A non-return check valve 64 togetherwith a spring 66 comprises conventional means which will permit readyflow of fluid `from the bottom compartment 36 to the upper compartment34 .upon downward movement of the piston hammer but will prevent reverseflow therethrough.

It is preferred, 'as shown in FIGURE 3 to provide an O-ring or seal asat 70 upon the circumference of the piston hammer to establish afluid-tight sealing engagement of the latter with the wall of thechamber in which the piston hammer is slidably disposed.

The control means further includes `a control piston or control valve 72which is slidably received in the bore Sil and chamber 54 and which ismounted upon and carried by the upper end of the bottom closure plug 24.It will thus be seen that the member 74 is stationarily mounted and thatrelative sliding movement between the valve of piston member 72 and theby-pass passages is effected by vertical reciprocation of the pistonhammer 32 and its piston rod or operating rod 30.

The arrangement is such that there is sufficient clearance providedbetween the piston 72 and the wall of the bore 50 to enable a slowleakage of iiuid through the bypass passage 52 and into or out of thechamber 54 as the piston is slowly pulled upward in the barrel of thedevice by upward thrust imparted to the operating rod by the string 12.It will be understood that the weight of the barrel 2t) and of the sub=16 attached thereto and of the fish when the sub is attached to thelatter will resist this upward pull and thus cause a relative upwardtravel of the piston hammer within the chamber of its barrel.

It will be understood that this upward travel during ie initial portionthereof is necessary relatively slow, being limited to the rate at whichhydraulic fluid can leak from the chamber 34 through the by-pass meansand pass through control piston 72 into the chamber 36. However, whenthis upward travel has reached such an extent that the upper end of thecontrol piston 72 clears the lo er end of the by-pass passages 56, therehas been established a substantially unimpeded flow of uid between thetwo chambers s0 that the piston hammer 32 can now travel rapidlyupwardly until its top surface 58 strikes the anvil surface 46 of thetop closure plug 22 and thus delivers the desired upward impact or blowto the body Ztl, to the closure plug 24 carried thereby and from thelatter to the fishing sub 16.

When the lifting member 30 is `a-gain lowered, the weight of the samewill cause the piston hammer to travel rapidly downwardly within thechamber within the body 2d fand the return means consisting of the valve64 and the associated passage arrangement will permit such returnmovement to occur rapidly.

Obviously, a series of such impulses can thus be given to effectloosening of the fish and facilitate its recovery by the device.

In the -device as so far described, it will be understood that thehydraulic liuid employed to control the rate of movement of the pistonhammer within the jar is cornpletely sealed within the device in aself-contained system. It is however possible to employ the sameprinciple of operation in a device in which the well fluid itself isemployed as the hydraulic fluid controlling the operation of the device.In this arrangement the structure is identical to that previously`described except for a modification shown in FIGURES' 6 and 7. In thisarrangement, the O-ring 23 is omitted from the top closure plug 22 and asomewhat larger clearance as at is provided between the top closure plug22 and the adjacent surface of the operating or piston red 30.Consequently, drilling mud or other well fluid can readily fiow into thetop chamber 34 of the barrel 20 above the piston hammer therein and thisiiuid will operate to regulate the rate of upward travel by means of theby-pass passage means and the return means in the same manner asdescribed in connection with the preceding embodiment.

The foregoing is considered as illustrative only of the principles ofthe invention. Further, since numerous modifications and changes willreadily occur to those skilled in the art, it is not desired to limitthe invention to the exact construction and operation shown anddescribed, and accordingly all suitable modifications and equivalentsmay be restored to, falling within the scope of the invention asclaimed.

What is claimed as new is as follows:

l. A hydraulic jar comprising a hollow body having a chamber thereinwith top and bottom closures, a piston hammer slidable in said chamberand having an operating stem slidably extending through said topclosure, said piston hammer having a iiuid tight seal engaging the wallof said chamber at all times and dividing said chamber into top andbottom compartments, said body having a surface disposed in the range ofmovement and path of travel of said piston hammer and constituting ananvil for the latter, a by-pass means establishing communication betweensaid compartments on opposite sides of said piston hammer for ow ofhydraulic fluid therebetween, a control means in said body forestablished slow leakage of uid from the top to the bottom compartmentduri-ng the initial upward lmovement of said piston hammer in saidchamber and establishing unrestricted liow during the remainder upwardmovement of said hammer piston, said control means being disposed insaid by-pass means l antisera for controlling iiow through the latterbetween said top and bottom compartments.

2. The combination of claim 1 wherein said chamber is of a uniform`diameter throughout at least that portion thereof which is traveled bysaid piston hammer.

3. The combination of claim 1 wherein said by-pass means comprisespassages extendino through said piston hammer, said passages beinginclined inwardly from their upper ends adjacent the periphery of thepiston hammer to their lower ends adjacent the longitudinal axis of saidpiston hammer, said control means comprising a member movable in one ofsaid passages and controlling flow therethrough.

4. A hydraulic jar comprising a hollow body having a chamber thereinwith top and bottom closures, a piston hammer slidable in said chamberand having an operating stem slidably extending through said topclosure, said piston hammer dividing said chamber into top and bottomcompartments, a by-pass means establishing communication between saidcompartments on opposite sides of said piston hammer for flow ofhydraulic liuid therebetween, a control means in said body forestablishing slow leakage of fluid from the top to the bottomcompartment during the initial upward movement of said piston hammer insaid chamber and establishing unrestricted how during the remainderupward movement of said piston hammer, said piston hammer having a boreextending upwardly from the bottom surface thereof and comprises acontrol chamber, said by-pass means comprising passages in said pistonhammer having one end of each opening into said upper compartment andhaving the other end of each opening into said bore, said control meansincluding a member -slidably received in said bore and restricting andthrottling tlow of fluid between said control chamber and said passages.

5. The combination of claim 4 wherein said control means member consistsof a piston valve relatively slidable in said bore and throttling thecommunication of the latter with said passages.

6. The combination of claim 5 wherein said piston valve is carried bysaid bottom closure.

7. A hydraulic jar comprising a hollow body having a verticallyelongated chamber therein with top and bottom closures, a piston hammerslidable with huid-tight engagement within said chamber and dividing thelatter into top and bottom compartments, said piston hammer including anoperating stem through which relative movement is given to said pistonhammer in said chamber, said body having an anvil engageable by saidpiston hammer during its sliding movement in one direction, by-passmeans in said piston hammer for :dow of fluid between said compartments,control means disposed in said by-pass means for restricting rate offlow through said by-pass means during the initial portion of upwardtravel of said piston hammer in said chamber and for eiectingunrestricted rate of how through said by-pass means during the initialportion of upward travel of said piston hammer in said chamber and foreffecting unrestricted rate of ilow through said oy-pass means duringthe remainder of the upward travel o said piston hammer in said chamber,said control means comprising a bore in said piston hammer extendingvertically upward from the bottom face of said piston hammer and apiston valve stationariiy mounted in said chamber and having sliding tin said bore with a slow rate of leakage therebetween, said by-passmeans including a passage in said piston hammer establishing continuouscommunication between said top compartment and with said bore by aninlet port at an intermediate location in the latter, said piston hammerand piston valve being so positioned that said piston valve will coversaid inlet port during said initial portion of said upward travel andwill uncover said inlet port during said remainder of said upwardtravel, iiuid return means establishing ilow between said compartmentsand including a non-return valve preventing flow from the top to saidbottom compartment but allowing free reverse flow.

S. The combination of claim 7 wherein said return means extends throughsaid piston hammer.

9. The combination of claim 8 wherein said return means communicateswith said bypass means.

10. The combination of claim 1 including fluid return means including acheck valve for establishing one way communication between saidcompartments for effecting how of fluid from the bottom to the topcompartment.

11. The combination of claim l0 wherein said return means extendsthrough said piston hammer.

12. The combination of claim 1l wherein said return means communicateswith said by-pass means.

13. The combination of claim l wherein said said top closure comprisessaid anvil engageable by said piston hammer.

14. The combination of claim 1 wherein said top closure comprises saidanvil engageable by said piston hammer, and said control means includesa piston valve carried by said bottom closure.

References Cited in the tile of this patent UNITED STATES PATENTS1,637,505 Wigle Aug. 2, 1927 1,927,836 Kightlinger Sept. 26, 19331,989,280 Kammerdiner lan. 29, 1935 2,645,459 Sutliff July 14, 19532,659,576 Linney Nov. 17, 1953 2,862,703 Harrison Aug. 13, 19572,828,822 Greer Apr. 1, 1958 2,851,110 Greer Sept. 9, 1958

